1. Field of the Invention
The present invention pertains to a stencil printing machine and a stencil printing method for the same, which performs stencil making processing and printing processing according to printing conditions, such as ink-saving printing or the like.
2. Description of the Related Art
In a stencil printing machine, which prints by pressing a printing paper against a perforated stencil sheet wrapped around a printing drum with a pressure roller, the stencil printing machine, which is possible to print under desired printing density by setting printing conditions, such as a pressure force (printing pressure force) or printing speed, is proposed by the present applicant in Japanese Patent Laid Publication No. 2593623.
According to the methodology disclosed in above publication, for example, the low cost printing to cut back ink consumption, ink-saving printing in consideration of the ecology for environment, etc. is also achieved by adjusting the printing conditions suitably so as thin printing density.
In an ink jet printing machine, methodology for reducing the number of printing dots (pixels) and cutting back ink consumption by extracting only dots relating to an appearance and an outline from image data expanded into a bit map format, forming an outline pattern, and printing only the outline pattern is disclosed in Japanese Patent Laid Open Publication (Kokai) No. H08-156247.
Although the print quality is reduced according to the ink-saving printing, the ink-saving printing is a function selected by user's own will from the viewpoint of giving priority to reduction of printing cost and the performance for environment over the printing quality. Therefore, an important subject is to provide a stencil printing machine and a method for stencil printing, which can prevent the reduction of the printing quality as much as possible and acquire more effect of the ink-saving printing.
However, if the pressure force (printing pressure force) for pressing the printing paper against the perforated stencil sheet wrapped around the printing drum with the pressure roller is reduced so as the thin printing density by using the methodology of the above-mentioned publication No. 2593623, although the reduction of the print quality is prevented, the effect of the ink-saving printing is not satisfactorily acquired.
On the other hand, if the printing dots except the outline dots is reduced by using methodology of the above-mentioned publication No. H08-156247, although the effect of the ink-saving printing is acquired up to a certain point, the printing quality is greatly reduced.